Stamping presses frequently comprise a ram operatively connected to an in-line air cylinder whereby the force applied by the ram to a work piece is equal to the force exerted on the ram by the driving cylinder. Thus to increase the force applied during the power stroke it is generally necessary to increase the size of the air cylinder or utilize, for example, auxiliary mechanical means, the latter decreasing the smoothness of press operation with corresponding diminished repeatability. Since it is less costly to manufacture air cylinders having longer strokes than to manufacture larger cylinders, it is desirable to provide an air driven stamping press utilizing a longer stroke to increase the applied pressure.
Various types of drive mechanisms provide a power stroke where the applied pressure increases to a maximum near the end of the stroke. However, for hot stamping and other applications it is desirable to maintain a relatively constant applied pressure throughout the stroke while also having the capability of high pressure operation without loss of repeatability.
Accordingly, it is an object of the present invention to provide a novel stamping press having a highly repeatable power stroke and exerting a force increased over that provided by the direct drive means for the press.
It is also an object of the present invention to provide such a press which utilizes pulley means having a mechanical advantage to increase the force exerted by piston/cylinder to augment the power stroke.
Another object is to provide such a press which utilizes an air cylinder having an increased stroke to augment the power stroke and which delivers a constant pressure throughout the stroke.